Expandable cannula and method of use

ABSTRACT

A cutting device includes an elongated shaft that extends between a proximal end and a distal end. A distal arm extends from the distal end of the elongated shaft. The distal arm includes an inner surface defining a cavity and an outer surface defining a blunt tip. At least one proximal arm extends from the distal end of the elongated shaft at a position proximal to the distal arm. The at least one proximal arm having an inner surface defines a cavity including a cutting portion configured to cut tissue.

FIELD OF THE INVENTION

The present invention relates generally to devices and methods for asurgical tool for creating access to and/or cutting a material orsubstance. More specifically, the devices and methods are useful forresecting nerve and/or soft tissue via a minimally invasive procedure toalleviate pain.

BACKGROUND

Standard methods of cutting tissue may include using a scalpel,scissors, and radio frequency energy. Electrosurgical procedures andtechniques using radio frequency energy are currently used since theygenerally reduce patient bleeding and trauma associated with cuttingoperations. Additionally, electrosurgical ablation procedures, wheretissue surfaces and volume may be reshaped, cannot be duplicated throughother treatment modalities.

Minimally invasive procedures in nerve and/or soft tissue such as thespine or the breast, however, are difficult to perform using standardscissors and scalpel. Furthermore, in a closed environment, radiofrequency current dissipates into the surrounding tissue causing adecreased ability to achieve a current at the cutting electrode ofsufficiently high density to initiate a cut. To overcome this problem,high power settings are often required to initiate the cut which oftenis painful and increases thermal damage to the tissue whether using astandard or a custom electrosurgical generator.

Another problem associated with cutting tissue is the control ofbleeding. Radio frequency energy controls bleeding by coagulating smallblood vessels. Another method of controlling bleeding is through the useof heat. For example, some commercially available scalpels use directheat to control bleeding. However, while the bleeding is generallycontrolled, the cutting of tissue is often slower than with radiofrequency energy and the knife edge readily dulls. Other commerciallyavailable scalpels use ultrasonic energy generally at 50 kHz to heat thetissue so as to coagulate severed blood vessels but cut slower than astandard electrosurgical electrode and are costly as a custom ultrasonicgenerator is required.

A further disadvantage of using radio frequency energy is the generationof smoke. The smoke is malodorous and can contain airborne viralparticles that may be infectious. Furthermore, the smoke often obscuresvisualization of the procedure. When the smoke becomes too dense, theprocedure is delayed until the smoke is released through one of thetrocar ports and after enough carbon dioxide gas has re-insufflated theabdominal cavity. This unnecessarily prolongs the operative time.

Radiofrequency (RF) energy is used in a wide range of surgicalprocedures because it provides efficient tissue resection andcoagulation and relatively easy access to the target tissues through aportal or cannula. Conventional monopolar high frequency electrosurgicaldevices typically operate by creating a voltage difference between theactive electrode and the target tissue, causing an electrical arc toform across the physical gap between the electrode and tissue. At thepoint of contact of the electric arcs with tissue, rapid tissue heatingoccurs due to high current density between the electrode and tissue.This high current density causes cellular fluids to rapidly vaporizeinto steam, thereby producing a “cutting effect” along the pathway oflocalized tissue heating. Thus, the tissue is parted along the pathwayof evaporated cellular fluid, inducing undesirable collateral tissuedamage in regions surrounding the target tissue site. This collateraltissue damage often causes indiscriminate destruction of tissue,resulting in the loss of the proper function of the tissue. In addition,the device does not remove any tissue directly, but rather depends ondestroying a zone of tissue and allowing the body to eventually removethe destroyed tissue.

Present electrosurgical techniques used for tissue ablation may sufferfrom an inability to provide the ability for fine dissection of softtissue. The distal end of electrosurgical devices are wide and flat,creating a relatively wide area of volumetric tissue removal and makingfine dissections along tissue planes more difficult to achieve becauseof the lack of precision provided by the current tip geometries.

In addition, identification of the plane is more difficult because thelarge ablated area and overall size of the device tip obscures thephysician's view of the surgical field. The inability to provide forfine dissection of soft tissue is a significant disadvantage in usingelectrosurgical techniques for tissue ablation, particularly inarthroscopic, otolaryngological, and spinal procedures.

Traditional monopolar RF systems can provide fine dissectioncapabilities of soft tissue, but may also cause a high level ofcollateral thermal damage. Further, these devices may suffer from aninability to control the depth of necrosis in the tissue being treated.The high heat intensity generated by these systems causes burning andcharring of the surrounding tissue, leading to increased pain and slowerrecovery of the remaining tissue. Further, the desire for anelectrosurgical device to provide for fine dissection of soft tissue maycompromise the ability to provide consistent ablative cutting withoutsignificant collateral damage while allowing for concomitant hemostasisand good coagulation of the remaining tissue.

Another problem with currently available RF nerve ablation devices isthat they attempt to destroy nerve tissue from a central locationincluding the tip of the device and a 3-D spherical or cylindrical zonearound it. As a result, the further away the resecting ability is fromthe central zone the less effective the nerve destruction. Consequently,often the nerve is not adequately ablated leading to continued painsymptoms.

Further, the health care practitioner may have difficulty positioningthe tip of the device in the optimal location to get an optimal andconsistent clinical result. This may also result in unwanted necrosis ofadjacent tissue, which can lead to clinical adverse events includingsubsequent repair of the necrotic tissue.

Other devices such as mechanical rongeurs can be used to remove softtissue. However, these devices require the insertion of relatively largecannulas that further complicate the surgical procedure and can causenerve compression and pain with variable clinical efficacy.

Accordingly, there is a need for devices and methods to provideefficient severing or cutting of nerve and/or soft tissue that can beused during a minimally invasive procedure and/or during an opensurgical procedure. Further, there is also a need for devices andmethods that provide fine dissection capabilities of nerve and/or softtissue. Devices and methods that do not cause a high level of collateralthermal damage and allow for the control of necrosis in the tissue beingtreated are also needed. Devices and methods that provide efficient,controlled and safe debulking of tissue would also be beneficial.

SUMMARY OF THE INVENTION

This application is directed to a surgical device for enlarging thediameter of a hole in tissue. The surgical device includes an elongatedshaft extending between a proximal end and a distal end and including anouter surface. A stylet is disposed within the elongated shaft. Thestylet is configured to retractably extend out of the elongated shaft soas to contact tissue. A cutting portion is disposed on a portion of theouter surface of the elongated shaft. The cutting portion is configuredto cut tissue as the shaft is inserted into the tissue so as to enlargethe diameter of the hole in the tissue. In one embodiment, the cuttingportion can also be a heating portion designed to cut tissue such thatthe tissue does not reapproximate its previous position after a workingcannula is removed.

In one embodiment, a device for expanding a diameter of a hole in tissueis provided. The device includes an elongated shaft extending between aproximal end and a distal end and including a first portion and a secondportion extending parallel to the first portion. A rod disposed withinthe elongated shaft, the rod being configured to retractably expand theelongated shaft such that the first portion and the second portion froma first collapsed orientation such that the first and second portion aredisposed adjacent to each other to a second expanded orientation suchthat the first and second portion are disposed at a distance from eachother so as to enlarge the hole in the tissue.

In one embodiment, a method of using a device to enlarge a hole intissue comprising cutting a hole in the tissue is provided. A cannula isinserted into or on the anatomy of a patient. The cannula comprises anelongated shaft extending between a proximal end and a distal end andincluding a first portion and a second portion extending parallel to thefirst portion. A rod is disposed within the elongated shaft, the rodbeing configured to retractably expand the elongated shaft such that thefirst portion and the second portion from a first collapsed orientationsuch that the first and second portion are disposed adjacent to eachother to a second expanded orientation such that the first and secondportion are disposed at a distance from each other so as to enlarge thehole in the tissue. The rod is manipulated by a medical practitioner toexpand the first and second portion to the expanded orientation toexpand the hole in the tissue. In the alternative, cannulas that do notexpand but are sequentially larger in diameter may be used to increasethe size of the working/hole in the tissue.

Additional features and advantages of various embodiments will be setforth in part in the description that follows, and in part will beapparent from the description, or may be learned by practice of variousembodiments. The objectives and other advantages of various embodimentswill be realized and attained by means of the elements and combinationsparticularly pointed out in the description and appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

In part, other aspects, features, benefits and advantages of theembodiments will be apparent with regard to the following description,appended claims and accompanying drawings where:

FIG. 1 is a perspective view of an embodiment of the device inaccordance with the principles of the present disclosure;

FIG. 2 is perspective view of components of the device shown in FIG. 1;

FIG. 3 is a perspective view of an embodiment of the device inaccordance with the principles of the present disclosure;

FIG. 4 is a perspective view of an embodiment of the device inaccordance with the principles of the present disclosure;

FIG. 5 is a perspective view of an embodiment of the device inaccordance with the principles of the present disclosure;

FIG. 6 is a side view of an embodiment of the device in accordance withthe principles of the present disclosure; and

FIG. 7 is a cross section view of components of the device shown in FIG.6.

DETAILED DESCRIPTION OF THE INVENTION

Devices for efficient severing or cutting of a material or substancesuch as nerve, soft tissue and/or bone suitable for use in open surgicaland/or minimally invasive procedures are disclosed. The followingdescription is presented to enable any person skilled in the art to makeand use the present disclosure. Descriptions of specific embodiments andapplications are provided only as examples and various modificationswill be readily apparent to those skilled in the art.

Lumbar spinal stenosis (LSS) may occur from hypertrophied bone orligamentum flavum, or from a lax ligamentum flavum that collapses intothe spinal canal. LSS can present clinical symptoms such as leg pain andreduced function. Conventional treatments include epidural steroidinjections, laminotomy, and laminectomy. Surgical interventions whichremove at least some portion of the lamina are usually performed througha relatively large incision, and may result in spinal instability fromremoval of a large portion of the lamina. Consequently, a percutaneousapproach which removes just enough tissue (lamina or ligamentum flavum)to be effective is provided and may be beneficial.

In one embodiment, a blunt stylet is nested within a cannula topenetrate soft tissue. An outer wall of the cannula has ring of exposedmetal to deliver RF energy to contact soft tissue. The tissue may eitherbe cut or heated. The remaining portion of outer wall of the cannula isinsulated. In one embodiment, successive cannulas may be placed over thestylet to increase the size of a hole in the soft tissue.

In one embodiment, the cannula has single or multiple rasps orgrater-like openings on the side wall. The rasp opening is configured tocut and enlarge a bony opening. The cannula is twisted about its axis toshave bone. The bony fragments are collected in the cannula lumen andmay be evacuated via suction or with mechanical method, such as anauger.

In one embodiment, the cannula is created from two halves of tubing.Each tubing half has ratchet feature that mates with correspondingratchet feature in other tubing half. An expandable stylet is placed incannula lumen to increase cannula diameter and separate the first halfform the second half.

The present disclosure may be understood more readily by reference tothe following detailed description of the disclosure presented inconnection with the accompanying drawings, which together form a part ofthis disclosure. It is to be understood that this disclosure is notlimited to the specific devices, methods, conditions or parametersdescribed and/or shown herein, and that the terminology used herein isfor the purpose of describing particular embodiments by way of exampleonly and is not intended to be limiting of the claimed disclosure.

As used in the specification and including the appended claims, thesingular forms “a,” “an,” and “the” include the plural, and reference toa particular numerical value includes at least that particular value,unless the context clearly dictates otherwise.

Ranges may be expressed herein as from “about” or “approximately” oneparticular value and/or to “about” or “approximately” another particularvalue. When such a range is expressed, another embodiment includes fromthe one particular value and/or to the other particular value.

Similarly, when values are expressed as approximations, by use of theantecedent “about,” it will be understood that the particular valueforms another embodiment. It is also understood that all spatialreferences, such as, for example, horizontal, vertical, top, upper,lower, bottom, left and right, are for illustrative purposes only andcan be varied within the scope of the disclosure.

For purposes of the description contained herein, with respect tocomponents and movement of components described herein, “forward” or“distal” (and forms thereof) means forward, toward or in the directionof the forward, distal end of the probe portion of the device that isdescribed herein, and “rearward” or “proximal” (and forms thereof) meansrearward or away from the direction of the forward, distal end of theprobe portion of the device that is described herein. However, it shouldbe understood that these uses of these terms are for purposes ofreference and orientation with respect to the description and drawingsherein, and are not intended to limit the scope of the claims.

Spatially relative terms such as “under”, “below”, “lower”, “over”,“upper”, and the like, are used for ease of description to explain thepositioning of one element relative to a second element. These terms areintended to encompass different orientations of the device in additionto different orientations than those depicted in the figures. Further,terms such as “first”, “second”, and the like, are also used to describevarious elements, regions, sections, etc. and are also not intended tobe limiting. Like terms refer to like elements throughout thedescription.

As used herein, the terms “having”, “containing”, “including”,“comprising” and the like are open ended terms that indicate thepresence of stated elements or features, but do not preclude additionalelements or features.

For purposes of the description contained herein, “vacuum” meanspressure within a space that is lower by any amount than atmospheric orambient pressure, and although not exclusive of a condition of absolutevacuum defined by a complete absence within a space of air, fluid orother matter, the term as used herein is not meant to require or belimited to such a condition.

The headings below are not meant to limit the disclosure in any way;embodiments under any one heading may be used in conjunction withembodiments under any other heading.

Reference will now be made in detail to certain embodiments of theinvention, examples of which are illustrated in the accompanyingdrawings. While the invention will be described in conjunction with theillustrated embodiments, it will be understood that they are notintended to limit the invention to those embodiments. On the contrary,the invention is intended to cover all alternatives, modifications, andequivalents that may be included within the invention as defined by theappended claims.

Radiofrequency (RF) ablation devices have been available to surgeons totreat many medical conditions, for example, in the treatment of tumorsin lung, liver, kidney, bone and other body organs. Pulsed RF has alsobeen used for treatment of tumors, cardiac arrhythmias, chronic andpost-operative pain, bone fracture and soft tissue wounds.

The components of the cutting device can be fabricated from biologicallyacceptable materials suitable for medical apparatuses, including metals,synthetic polymers, ceramics, thermoplastic and polymeric materialand/or their composites. For example, the components of the holdingdevice, individually or collectively, can be fabricated from materialssuch as stainless steel alloys, commercially pure titanium, titaniumalloys, Grade 5 titanium, super-elastic titanium alloys, cobalt-chromealloys, stainless steel alloys, superelastic metallic alloys (e.g.,Nitinol, super elasto-plastic metals, such as GUM METAL® manufactured byToyota Material Incorporated of Japan, Fe—Mn—Si and Fe—Ni—Co—Ticomposites), ceramics and composites thereof such as calcium phosphate(e.g., SKELITE™ manufactured by Biologix Inc.), thermoplastics such aspolyaryletherketone (PAEK) including polyetheretherketone (PEEK),polyetherketoneketone (PEKK) and polyetherketone (PEK), carbon-PEEKcomposites, PEEK-BaSO4 polymeric rubbers, polyethylene terephthalate(PET), fabric, silicone, polyurethane, silicone-polyurethane copolymersbased materials, polymeric rubbers, polyolefin rubbers, semi-rigid andrigid materials, thermoplastic elastomers, thermoset elastomers,elastomeric composites, rigid polymers including polyphenylene,polyamide, polyimide, polyetherimide, polyethylene, epoxy, andcomposites of metals and calcium-based ceramics, composites of PEEK andcalcium based ceramics, and combinations of the above materials.

Various components of the holding device may have material composites,including the above materials, to achieve various desiredcharacteristics such as strength, rigidity, elasticity, compliance, andbiomechanical performance, durability and to provide a non-sticksurface. The components of the holding device may be monolithicallyformed, extruded, coextruded, hot molded, cold molded, press molded,integrally connected or include fastening elements and/or couplingcomponents, as described herein.

In one embodiment, as shown in FIGS. 1-3, device 10, in accordance withthe present disclosure, includes an elongated shaft 12. Shaft 12 extendsbetween a proximal end 14 and a distal end 16. Shaft 12 includes aninner surface 18 and an outer surface 20. Inner surface 18 defines apassageway 22. It is envisioned that all or only a portion of shaft 12may have various cross section configurations, such as, for example,cylindrical, flat, oval, oblong, triangular, square, polygonal,irregular, uniform, non-uniform, offset, staggered, undulating, arcuate,variable and/or tapered. It is contemplated that surfaces 18, 20includes various surface configurations, such as, for example, smooth,rough, mesh, porous, semi-porous, dimpled and/or textured. In variousembodiments, the navigational sources can be coupled with pre-procedureimaging means such as for example, CT, MRI, PET scan, etc. so that thetarget nerve or soft tissue to be cut can be identified and accuratelylocated during the procedure. In some embodiments, shaft 12 can beoperatively connected to semi-steerable or navigational sources foreasier guidance into tissue. A stylet 24 is configured for retractableplacement into and through passageway 22 of shaft 12 such that a distalend 26 extends past distal end 16 of shaft 12 to contact tissue.

A cutting portion, such as, for example, a cutting band 28 is disposedaround surface 20. In one embodiment, cutting band 28 includeselectrodes 30 configured to emit a RF frequency adapted for cuttingnerve and/or soft tissue. In one embodiment, cutting band 28 isconfigured to emit pulsed plasma signals adapted for cutting nerveand/or soft tissue. In one embodiment, device 10 includes anelectrically insulated layer adjacent to and exposing cutting band 28such that the energy transmitted from the RF frequency and/or the plasmais centralized at cutting band 28. In some embodiments, the coating orinsulating layer can be glass or ceramic having a thickness from about0.005 to about 0.5 mm thick or from about 0.01 to about 0.2 mm thick. Byrotating shaft 12 back and/or forth the RF or plasma signals will cutthe tissue and enlarge the hole in the tissue. In one embodiment, thering extends around either the majority of the entire circumference orthe entire circumference of the cannula so that the cannula does nothave to be rotated.

In one embodiment, shaft 12 includes a connection to engage a vacuum(not shown) to remove the resected nerve and/or soft tissue.Alternatively, an additional channel is possible for delivering fluid tothe surgical site. At its proximate end, shaft 12 can be operativelyconnected to the vacuum for providing suction to resected nerve and/ortissue. A vacuum line may be used to transmit vacuum from a vacuumsource (not shown) to a receiving aperture connected to shaft 12. Thevacuum is in communication with opening 22 such that as tissue isresected from a target area, the tissue will be removed via suction. Thevacuum may be provided inside opening 22 or, alternatively, may beprovided through an additional lumen separate from opening 22. Anysuitable aspirator, cylindrical or otherwise, or other mechanism thatcreates vacuum upon the movement of an actuating member thereof, may beutilized as a vacuum source, such as, for example, a syringe ormechanical vacuum.

The present disclosure also provides methods for cutting or resectingnerve and/or soft tissue. The methods comprise positioning a distalregion of shaft 12 of device 10 within a hole in tissue. Distal end 16is positioned at the area where the tissue enlarged. To enlarge thediameter of the hole, shaft 12 is rotated back and forth, shown byarrows A and AA, such that cutting band 28 burns or cuts the tissue toenlarge the hole. In the alternative, a larger cannula is inserted inorder to increase the diameter.

In one embodiment, a diameter d increases from distal end 16 to proximalend 14 such that movement of shaft 12 into the hole allows the largerdiameter portion of shaft 12 to enlarge the hole. In one embodiment,increased diameter shafts 12 can be placed over a smaller diameter shaftsuch that the hole is enlarged as the increased diameter shaft is placedover the smaller diameter shaft.

In one embodiment, as shown in FIG. 4, shaft 112 includes a cuttingportion 128 that includes a rasp or grater-like cutting opening 129. Asshaft 112 is rotated the rasp opening 129 cuts or shaves tissue toenlarge the hole. Cut tissue fragments are collected in passageway 122of shaft 112. Rasp opening 129 is sharp so as to facilitate cutting ofbone tissue. The vacuum within or outside of shaft 12 is utilized toremove the cut nerve, soft tissue, and/or bone tissue such that device10 can be reinserted for additional cutting.

The present disclosure provides for a method for cutting or resectingbone tissue using surgical device 110. Distal end 116 is positioned in ahole at a predetermined target area by a medical practitioner. Invarious embodiments, navigational sources can be coupled withpre-procedure imaging means such as for example, CT, MRI, PET scan, etc.so that the target nerve or soft tissue to be cut can be identified andaccurately located during the procedure. Once distal end 116 ispositioned at a targeted hole on a bone that is to be enlarged, shaft112 is rotated in a circular motion such that rasp opening 129 cutsevenly and circumferentially to enlarge the hole in the bone tissue. Avacuum within or outside of shaft 112 is utilized to remove the cutnerve, soft tissue, and/or bone tissue such that device 110 can bereinserted for additional cutting.

In one embodiment, as shown in FIGS. 5-7, shaft 212 extends between aproximal end 214 and a distal end 216. Shaft 212 includes an innersurface 218 and an outer surface 220. Inner surface 218 defines apassageway 222. Shaft 212 includes at least two portions, such as, forexample, a first portion 224 and a second portion 226. Portions 224, 226are configured to retractably expand shaft 212 such that portion 224 andportion 226 move from a first collapsed orientation in which the firstand second portion are disposed adjacent to each other, to a secondexpanded orientation in which the first and second portion are disposedat a distance from each other so as to enlarge the hole in the tissue.

An expandable stylet 228 is configured to be placed within shaft 212such that expansion of stylet 228 causes expansion of shaft 212. Stylet228 is configured for retractable placement into and through passageway222 of shaft 212 such that as stylet 228 moves through passageway 222,stylet 228 expands shaft 212 by pushing portions 224 and 226 away fromeach other in the direction shown by arrow B. In one embodiment, a rod250 is engaged with stylet 228 by a ratchet mechanism or as shown, athreaded outer surface 252 of rod 250. Inner surface 230 of stylet 228includes a threaded surface 232 configured for engagement with threadedsurface 252. As rod 250 translates through stylet 228, threaded surface252 engages threaded surface 232 to expand stylet 228 and portions 224,226, as shown in FIG. 7. As such, shaft 212 inserted within hole H hasan initial diameter of d1, as shaft 212 expands, hole H and shaft 212are enlarged to a diameter d2, wherein d2 is large than d1. Threadedsurfaces 252 and 232 allow for incremental enlargement of hole H so asto enlarge hole H slowly to prevent damage to the tissue.

In one embodiment, shaft 12 is operatively coupled to a source ofnavigational capability to allow easier pushing through the tissues. Invarious embodiments, the methods of cutting disclosed herein can includea pre-procedure step wherein the probe or needle can be coupled to a CTor MRI machine so that the target nerve and/or soft tissue to be cut canbe identified and accurately located during the resection procedure.

The methods for cutting described hereinabove allow complete resectionof the nerve avoiding the problems and partial effectiveness of currentRF and cryoablation devices available in the art, and also allow foreasier, more efficient, more complete, and safer removal of soft tissuethat is causing stenosis pain symptoms.

It will be apparent to those skilled in the art that variousmodifications and variations can be made to various embodimentsdescribed herein without departing from the spirit or scope of theteachings herein. Thus, it is intended that various embodiments coverother modifications and variations of various embodiments within thescope of the present teachings.

1-12. (canceled)
 13. A cannula for expanding a diameter of a hole intissue: an elongated shaft extending between a proximal end and a distalend and including a first portion and a second portion extendingparallel to the first portion; and a rod disposed within the elongatedshaft, the rod being configured to retractably expand the elongatedshaft such that the first portion and the second portion move from afirst collapsed orientation such that the first and second portion aredisposed adjacent to each other to a second expanded orientation suchthat the first and second portion are disposed at a distance from eachother so as to enlarge the hole in the tissue.
 14. A cannula as recitedin claim 13, wherein the rod is threadably engaged with an inner surfaceof the elongated shaft such that translation of the rod through theelongated shaft expands the first and second portion of the elongatedshaft.
 15. A cannula as recited in claim 13, wherein the rod and theelongated shaft include a ratcheting connection such that the first andthe second portion can be incrementally expanded so as to expand thehole in the tissue and cannula can be locked in the expandedorientation.
 16. A cannula as recited in claim 13, wherein the rod ishollow and the elongated shaft further includes an attachment to avacuum to produce suction to remove tissue captured in the elongatedshaft.
 17. A cannula as recited in claim 13, wherein the elongated shaftis configured to receive a surgical tool.
 18. A method of using a deviceto enlarge a hole in tissue comprising: cutting a hole in the tissue;inserting a cannula comprising an elongated shaft extending between aproximal end and a distal end and including a first portion and a secondportion extending parallel to the first portion; and a rod disposedwithin the elongated shaft, the rod being configured to retractablyexpand the elongated shaft such that the first portion and the secondportion from a first collapsed orientation such that the first andsecond portion are disposed adjacent to each other to a second expandedorientation such that the first and second portion are disposed at adistance from each other so as to enlarge the hole in the tissue; andmanipulating the rod to expand the first and second portion to theexpanded orientation to expand the hole in the tissue.
 19. A method ofcutting tissue as recited in claim 18, including the step of capturingthe cut tissue in the elongated shaft.
 20. A method of cutting tissue asrecited in claim 18, including the step of suctioning the cut tissue outof the elongated shaft.